A number of documents have appeared in the literature describing the scientific basis for use of probiotics, or DFM's (direct feed microorganisms), as intestinal inoculants for production animals. Since Metchnikoff's early reports, several studies have shown the ability of lactobacilli, for example, to suppress coliform growth. Feeding viable Lactobacillus acidophilus cells to young dairy calves was shown to reduce the incidence of diarrhea, and increase the numbers of lactobacilli and reduce coliform counts in feces.
Probiotics for animals are bacterial or yeast preparations that are administered orally or added to feeds. The most commonly used animal probiotics are strains of the lactic acid bacteria (LAB) species, particularly those classified in the following genera: Lactobacillus, Lactococcus and Enterococcus. Included among these are the following species: Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus plantarum, Lactobacillus casei, Lactobacillus lactis, Lactococcus lactis, Lactococcus thermophilus, Lactococcus diacetylactis and Enterococcus faecium. Besides these LABs, some species of Bacillus (Bacillus subtilis, Bacillus toyoi) and yeasts and molds (Saccharomyces cerevisiae, Aspergillus oryzae, and Torulopsis sp.) are used.
It is generally held that during periods of low disease resistance, such as stress, undesirable microorganisms are able to proliferate in the GI tract of animals, humans included. Maintaining a normal, healthy balance of microorganisms is deemed to be critical during for example such stressful periods. The concept underlying use of probiotics therefore is that if sufficient numbers of an appropriate microorganism(s) are introduced into the intestinal tract (i) at times of stress and/or disease, (ii) at birth, or (iii) after antibiotic treatment (when minimal LAB are present), the negative consequences of the microbial imbalances can be minimized or overcome. Using such preparations of live, naturally occurring microorganisms helps restore and maintain the proper balance of beneficial microbes in the GI tract during times of stress, disease, and following antibiotic therapy. Some of the major problems or limitations encountered in commercial scale application of probiotics to animals are                (i) the use of correct and documented probiotic strain for the purpose, and        (ii) the availability of suitable delivery systems, and        (iii) the ability to get the probiotic preparations to the animals as quickly as possible after birth. This is particularly true in animal production when pelletized feeds are used, as is the case in the poultry industry. The pelletization process generally includes one or more heating steps involving temperatures high enough to pasteurize or sterilize the feed components, thereby precluding incorporation of viable microorganisms into these feeds prior to pelletization.The invention herein solves those problems with the undesired microorganisms as described below.        